| 초록 |
Mercury (Hg) has been considered hazardous because of its toxicity and bioaccumulation property. Stationary combustion source still emits significant amounts of flue gas containing the elemental form of Hg (Hg0). Although the Hg0 is very difficult to remove as it is insoluble and hard to capture without additional treatments, VOx/TiO2 catalyst, known as SCR catalyst, can oxidize the Hg0 into Hg2+ which is soluble and easily removed. Here, Hg oxidation activity was investigated using density functional theory (DFT) calculations based on the Eley-Rideal (E-R) mechanism. By using reduced and bare TiO2 with anatase phase and those with rutile phase, the effects of TiO2 phase and reduction treatment on the activity were studied; notably, the oxygen vacancy on the reduced TiO2 led to structural transformation of V2O5, thus changing the oxidation state of V from 5+ to 4+. This work demonstrates the necessity of cautious pre-treatment of TiO2 support and gives a guidance about which TiO2 phase should be chosen to achieve improved Hg oxidation activity. |
